Wednesday, August 01, 2007

LS9, a company based in San Carlos, CA, and founded by geneticist George Church, of Harvard Medical School, and plant biologist Chris Somerville, of Stanford University, had previously said that it was working on what it calls "renewable petroleum." But at a Society for Industrial Microbiology conference on Monday, the company began speaking more openly about what it has accomplished: it has genetically engineered various bacteria, including E. coli, to custom-produce hydrocarbon chains.

Next year LS9 will build a pilot plant in California to test and perfect the process, and the company hopes to be selling improved biodiesel and providing synthetic biocrudes to refineries for further processing within three to five years.

I have written about these custombiofuels before. But what was interesting about this article, was this tidbit on yield:

LS9's current work uses sugar derived from corn kernels as the food source for the bacteria--the same source used by ethanol-producing yeast. To produce greater volumes of fuel, and to not have energy competing with food, both approaches will need to use cellulosic biomass, such as switchgrass, as the feedstock. Del Cardayre estimates that cellulosic biomass could produce about 2,000 gallons of renewable petroleum per acre.

Producing hydrocarbon fuels is more efficient than producing ethanol, del Cardayre adds, because the former packs about 30 percent more energy per gallon. And it takes less energy to produce, too. The ethanol produced by yeast needs to be distilled to remove the water, so ethanol production requires 65 percent more energy than hydrocarbon production does.